1. Field of the Invention
The present invention concerns an improved method of preparing high molecular weight polyphenoxy ethers from alkyl phenols. More particularly, the invention relates to a method of preparing high molecular weight polyphenoxy ethers by contacting a solution of an alkyl phenol with oxygen or an oxygen containing gas in the presence of an alkaline material selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates and a catalyst system comprising an activated or precipitated alumina support on which are deposited mixed oxides of manganese, chromium and copper.
2. DESCRIPTION OF THE PRIOR ART
It is now well know that alkyl-substituted phenols can be oxidized to yield in general self-condensation products including diphenoquinones and polyphenoxy ethers.
In preparing these materials, a variety of catalysts have previously been sugggested including several types of manganese catalysts. The use of manganese catalysts in combination with other compounds is also known in the art. For example, the use of a manganese catalyst in phenol oxidation was disclosed in U.S. Pat. No. 3,825,521 issued to Asahi-Dow. This patent discloses the preparation of polyphenoxy ethers in the presence of a homogeneous chelate type catalyst comprising at least one divalent manganese salt and at least one selected amino compound. U.S. Pat. No. 3,787,361 issued to Sumitomo Chemical discloses a similar process in the presence of a homogeneous tertiary catalyst system composed of a manganese compound, a primary amine and an alcohol. It is also known that catalyst systems comprising a variety of different metals including manganese, chromium and/or copper have utility in a variety of chemical reactions. For example, U.S. Pat. No. 3,216,954 assigned to E. I. DuPont deNemours and Company discloses catalysts comprising a number of different metals for use in converting combustion products containing nitrogen oxides, carbon monoxide and hydrocarbons.
In accordance with the present invention there has now been discovered a method of preparing a high molecular weight polyphenoxy ether of an alkyl phenol, said method comprising contacting a solution of the alkylphenol with oxygen or an oxygen carrying gas in the presence of an alkaline material selected from the group consisting of alkali metal alkoxides, hydroxides, and alkali metal carbonates, the improvement which comprises reacting the alkyl phenol in the presence of a heterogeneous catalyst system containing mixed oxides of manganese, chromium, and copper supported on activated or precipitated alumina in which the metals are present by weight of the catalyst system from abou 5 to 25 percent chromium, 3 to 15 percent copper and in which the weight ratio range of manganese to chromium is 1.9-0.9 to 1.
An additional advantage of the process of the invention is the ability to selectively control the molecular weight of the polyphenoxy ethers.